The capability of spaceborne Global Navigation Satellite System‐reflectometry (GNSS‐R) for Greenland ice sheet melt detection is investigated using the TechDemoSat‐1 satellite (TDS‐1) data. The melt detection is based on the sensitivity of GNSS‐R signal to the presence of liquid water in snow pack. Statistical analysis during the 2018 melt season shows melt detection using GNSS‐R is possible with an agreement of 90% comparing to the microwave radiometer (MWR) data. In 37% of the cases GNSS‐R detects melting when MWR does not. The inconsistency observed between GNSS‐R and MWR is mainly due to the different features of the two observation concepts and the limitations of currently available GNSS‐R data. Furthermore, the large penetration depth of the GNSS signal can potentially provide complementary information on melt occurrence in ice sheet subsurface. These results show the potential of future GNSS‐R missions for ice sheet melt detection. Plain Language Summary: Melt of Greenland ice sheet (GrIS) plays important roles in sea level change, global climate, and other areas of global environmental issues. Satellite microwave remote sensing has been increasingly used to produce maps of snow melt over Greenland during the past decades. The use of signals transmitted by navigation satellites after reflected from the Earth surface, known as Global Navigation Satellite System Reflectometry (GNSS‐R), provides a cheap solution of measuring the Earth surface with exceptional spatiotemporal coverage. Using the data collected from U.K. TechDemoSat‐1 mission, we investigate the feasibility and performance of spaceborne GNSS‐R for GrIS melt detection. The results obtained with GNSS‐R measurements give good agreement with GrIS melt data from other microwave sensors and also show potential of providing complementary melt information in deep layers of the GrIS due to the penetration of GNSS signal into the snow pack. These results, obtained from a technique demonstration platform, show the potential of future GNSS‐R missions for provide high spatial and temporal resolution melt data over the Greenland and Antarctica ice sheet. Key Points: Greenland ice sheet melt detection is demonstrated using spaceborne GNSS reflectometry for the first timeResults show good agreement with the Special Sensor Microwave Imager/Sounder Greenland ice sheet melt productGNSS reflectometry shows potential to provide complementary information on melt occurrence in ice sheet subsurface [ABSTRACT FROM AUTHOR]
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